The proportion of time, grazing animals are out of pasture varies a lot, according to breeding intensity, region and landscape. With grazing cattle, excretions are not spread evenly on the grassland, but in form of small point sources, which might cause NH3-emission or NO3-leaching. The N efficiency of N excreted during grazing is low and therefore usually also mineral fertiliser is applied to grazed grassland. The risk on nitrate leaching from grazed grassland is depending on the grazing intensity (LU per hectare, duration) and period (high leaching in autumn), fertiliser N application rate, site specific factors and weather conditions.
The indicator animals out on pasture is a rather imprecise indicator, as there is no mentioning of the timespan, the animals remain on the same plot; also, there is no information on additional mineral fertilisation of the plot that has been grased. Animals out on pasture therefore seems to be a rather weak indicator for the possible leaching of nitrates.